This invention relates generally to a cooling efficiency meter and associated circuitry for use in monitoring relative changes in the long term energy consumption of an air conditioner system occasioned by the making of manual adjustments in the operating controls of the system.
In recent years, there has been a growing demand for conservation of electrical energy because of the impact of such consumption upon coal and other natural resources, environmental quality and costs. While consumers of electrical power are generally concerned about all these factors, a direct and immediate concern to all is the purchase cost of such energy. A major energy consuming facility in modern homes, offices and other buildings is the air conditioner. It is, therefore, of particular importance that such facilities be operated in the most cost efficient manner possible, consistent with the minimum comfort requirements of their users. To accomplish this, it is necessary to detect changes in the operator controllable parameters of the facility which have a substantial impact upon long term energy consumption such as changes in thermostat settings, fan motor speed, vent door openings and closings, and so on. By "long term" energy consumption is meant that energy consumption which can have recognizable impact upon the users' monthly utility bill as opposed to momentary or short term energy consumption which, while momentarily affecting the power drawn by the facility, has little if any adverse effect upon such utility costs.
One prior art device generally pertinent to this subject is that disclosed in U.S. Pat. No. 4,049,044 issued to D. J. Cohen on Sept. 20, 1977 entitled Heat and Cooling System Consumption Meter. That device is a monitor for heating and cooling energy consumed by a unit of a multi-unit apartment or office building and is responsive to thermostat settings and blower speeds. A digital pulse generator is coupled to an integrating circuit which, in turn, generates an extended pulse which is thereafter amplified and transmitted to a pulse counter.
One problem encountered with such prior art devices is the relative complexity of the circuit in terms of the number and variety of components employed. Another problem encountered is that the pulse counter can not operate when the thermostat contacts are open, whereby energy consumed by the facility resulting from continuous fan operation is not detectable when the compressor is inoperative. Moreover, since the subject device indicates that energy consumption increases proportionally as fan speed is increased, the device is a monitor of momentary or short term energy consumption rather than long term energy consumption such that it may not accurately represent cost efficiency under all possible variations of the operator control functions. For example, while increases in the speed of the fan motor will increase the momentary power drain of the air conditioner, the improved efficiency of heat exchanger operation caused by increased fan speed will reduce the running time for the compressor for a given thermostat setting resulting in an actual reduction in the long term energy consumption.
The device of my invention substantially overcomes such difficulties and inaccuracies typically encountered in prior art monitoring systems.